Automatic telephone system.



Pmendsept. 10,1518. 5 sHETs-sHEET s.

A. M. MALMBEHG.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION man Amzl. |914.

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A.' M. MALMBEHG.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED APR.27.19I4.

1,278,365. Patented Sept. 1o, 1918.

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'13 UI r IIIIIIIIHI A. M. MALMBERG.

AUTOMATIC TELEPHONE SYSTEM. APPLICATION FILED APR.21.19`14.

s SHEETS-SHEET a.

Patented Spt. 10, 1918.

. [N1/:Mraz AND/5x25 M MAL/wsse@ .AM/.2M @i //m/.f/W

TTOENE YS A. M. MALMBERG. AUTOMATIC TELEPHONE SYSTEM.

APPLICAUQN vFILED APR. 21T 19H.

Patentedept. 10, 12118.

Patented sept. 10,1918.

A, M. MALMBERG. AUTUMATIC TELEPHONE SYSTEMI APPLlcnwN HLED mijn 1914. 1,278,365.

)Mm/555:5 u

fr nu STATES VPAll'J'lSTT 5 nbifhave invented :certain new` indinsel'll `.Ifijil'iro e'ments in Automatic Telephone Sys# f:eii`1's,jf jf which the' following is 'a specificav to. "j jM'y inv yalitomat-ic 'telephone'systems and has for its object the provision of 'a system in which l glhmimproved trunking arrangement is :eul- *il* p'l'oyefl,5'` whereliy the amount of apparatus 'Herctofore. in automatic systems. attempts have been made to connect a calling u ziifafcalleel line. Aby-a more or direc-t; l lpa'th after a connectionl has been established )etween said lines, thusv enabling the ap-l 20 params ei'uployed for establishing .the connection vto bereleasd. So far. as Iam aware, liiwiver, Vsuch attempt-s have heen" unsucl `esszflil and the object of my, inventii'in-s to provide such afsy'stelu in' ywhich certain apprutus is' employed fol" establishln ,a connecon between a Calling and a cal ed suhcrilxes line, and then afterthis eonnection lisbeen established a more directr path is lablished between the two linesand part offth apparatus employedfo'r originally 'esiiiadelaeoessible for-other calls.

Further objects ofmy invention relate to velnents in certain'of the switches em- I i115"edfrestblishingthes :zonnet:tions.I

3' ini'ention will be inore readily under'- by vr'ferel'ice to the acconrfpanyingv daings; in 'which I have illustrated` my i talen vogelzher represent In circuit connection between a. call Referring to specificano; of migre @uit appuntim'a nl s1, me wenn. l

tioiLA 2) and a'elled silli-y m'al obstruction of the secondary" n. ninguna, or Cameco, ILLINOIS; AssIgN 'ro AU'rL'nc ELEC'rBI comm, or cmcaeo, xLLmoxs, ,A conron'nox ogirmmoxs AU'romnxc Murnau: srs'rmt.

Patented Serbio, 191s.

lows: vThe apparaus'shovrn, exclusive 'of that within the; .damn uam-m Qtireigleit` of the figure, l-'epresel'ltgsyt 'e apparatus :fused in'maknig local "cal mi a ten thousand line ofhce ofa' one hun 'The,uppzl'mtusmthin the' dottedsquare represents "the" "apparatus by means of which callsl may be made from -anotheroflice of 'ntion relates to improvements 1n the system into this particular oflic'e; and there will be as many duplications' 'of these last as there areofher exchanges. There are Shown in this' figure several groups lof subscrilm's'fsu'l'rstations M,- M2, etc., theline comluctors` ofc-ach of which terminate in individual trunk-selecting or line switches QN'. X, etc. For Vthepullpose of being called these lines have terminals" in the banks of he arranged in horizontal rows or levels.V

cess tovroups oftrunk lines which lead to so-call `Secondary linejswitches P. The,

. switches P here access-to trunk lines! ,which lead to first selectors R and' also have' access i to trunk lines t which lead to special a ial'jy cllini devices' S. Then `a-s'witclpY is operated7 :lue t 0 being seizedl by -the line The ifnlividual switches N of each of the' i groups of subscribers 'stations M have aoswitch of a lcalling line, connection 'willbe made with an idle fins! selectoeli. It will.- 'presently be.' shown that when" n connector 0 finds :refilled line the subscriber is not ret,sifgnalefhbut the line switch of the called line first oieratesf totirunklo a' secondary l'irre'si'wfitch` and thesaid eec'im'dary switch,

tli'e' "anailiaryfY calling deiiices` S. 'It will =b nrilerstood 'that ,theAswitchesV can be pro`V "V vided with as ymany"l trunks' is fourni'V ne A-esaaryr Each, liuc"siviteh may beivenj there would he @secondary line" swtch'repf resentilrg4 leach primari:VA grou i in@ veuch onda'r'y. I't'iwill henn'lerstrj lso that the' secondary line switches. m'" vlltl ed los access 'to trunks t2 leading to tertiary line switches T. Associated with each ofV the switches T isy a special connector U. The banks of these connectors comprise trunks leading to the normals of each-of the calling devices S in the oice. The selectors R also have'access to trunk lines t3, which are outoing trunks, to other oiices of the system...

hetertiary line switches T have accessto trunks leading to second selectors V, which in 'turn have access to trunks leading to third selectors WV in the various 4thousands of this ofiice. These tertiar switches also have access to as many trun s as areinecessary. The third selectors W have access to trunks leadin to the various grou-ps of connectors@ 1n their particular thousand. Although the bank contacts of all the second selectors V shown in Fig. v1 are repref sented as being multiplied together, it is to be understood that any other known or desired multiplingarrangement of the selectors may be employed.

yIn' general' he operation of the system -shown m Fig. 2 is as follows Upon there- Inoval 'of the receiver by the calling subscriber, his line switch C operates to select a trunk. line leadingto a secondary line switch E, which in turn operates to select anv idle first selector F. The subscriber operateshis calling device to cause'the selected `first' selector to extend connection to any ldle tertiary -line 'switch EL in the section or division of the exchange to which .the called subscriber belongs. Assuming that. the tertiary switch E has been seized, the same then operates to select an idle second 'selector nector -H in the section. or division ofthe particular thousand to whichthe called subsoriber belongs.;v Assuming 'that the call connector' H has been seized, the same is then operated to extend the connection to the normals'ofthe called line. .As ar'esult theline switch Clo the'called line-operates as if the called subscriber had removed his receiver to make acall anilselects ya trunk line leading to a secondary line switch'lE?, which v`in turn Operates to select an idle cal-ling de- -vice Kf, -as'Lhas previously been explained.

The calling` deyice then operates Ato call its own number-bytransmittlng a series. of

impulses back throu hf-,thef secondary switch E2, the line switch A-,tthu vcall connector H,

-third selector F2, second-selectorl" and the tertiary line switch to the speclalsconnamens nector H. The connector H thereupon o A erates'in response to :the numberfca'llev by t' e calling' device K and makes connection with .the particular trunk inA its bank which leads tothe callin device K. The-calling and called subscrl ers lines are now connected by way of the line switch C, secondary line'switch E, first selector F, special .connector H", secondary line switch Ez and? the line switch C. The s'econds'e'lectorF., thirdjselector F? and the call connector H are released as soon as the connector H finds the instrument K 'and the-said switches are made available for use in sttingupvother connections.4 Should 'a subscriber .in another oiiice similarto the office shown in Fig. 1 desire to incoming second selector F3. for example, in

the nect1on is completed in the same manner as in thelocal call alread eXplained-`that-.is, the special connector 2 will connect with the trunk. A The automatic subst-ation A (Fig. 2) cornprises the usual receiver 2,' transmitter 3,' ringer 4 and condenser 5. Bein an autof matic substation it is also prov'i ed'` witha suitable call-sending mechanism'for'control- 4 ling the automatic switches, which mecha-` nism is represented diagrammatically by a pair of impulse springs 6 and 7 and an 1m- Eu'lse wheel 8, which latter may be controlled. ya d ialvprovided with linger holes 'in such oup V and the remainder of the. cona way that the impulsesprings may be inonientzrrily separated a number of tlmes corresponding to therespective digits of the numbervof the called subscriber.

The su-bscrbers individual switch C (Fig. 1) is of the general type of 'subscriber-s switch shown 1n British 4'patent to R. James No.v 26,301 of 1906, which is vWell known in the art. vThe line switch comprises amongothe'r details a flunger -(not shown)`- attached to the end o aso-called plunger arml 18 which is. controlled by the magnet- 26T. The magnet 267 comprises two windin namely, a pull-in wlnding 15 and a ho ding winding 35.' The pull-.in winding' 15 operates the plunger arml 18, while the holding winding 35 is only strong enough to of such sets,vv each set forming the terminal of a trunk line lending'to a Secondary line switch. yErich trunk line is connected in i multiple with the corresponding springs of n ll the line switches of the grupmhich ,is controlled by them-ster switch D. The Switch C is controlled by the subscriber through the niediini of the line relay 9, iis will hereinafter be more. full explained. The tertiary line switch E is similar to the line switch Cl The master switch D (Fig. .2) is of the Same general tjrpe as that disclosed in Britishpatent -to R..\V..Jii ines No. 26,301 of ,1906. above referredto, beingyhowever. more nearly of the particular" type disclosed in BritishY atent `to T. G. Martin No. 1410 o! .1910.` f he function of the nmsterswitcli, as is Well known, is to maintain the plinigersof' ll the idle line switches i" position to engage the terminal of an idle trunk line; The insister switches D. and D2 n re the same as the master switch D. 1

The secondiiityline `switch E. v(,Iigx--,.,.5, (i and conprises a bank of contacts-secured between tie plates 268 and 269 (Fig. 5). This bankcoin-prises four Sets or groups of contacts270, 271, 272 and 273 and the wipers -40,'-i8, 51 and 274- ilre proided for wiping vover andmaiking contact with these contacte. These wipers, `together with the two ratchet wheels 27 5 and 276, are securedl to the shaft l27"?. There is- 'also secured to tliesha'ft 277 a notched segment 278'for the purpose of j engaging with a retaining V'ari 279. re-

taining 'annie pivoted litt 280 and at its end ie provided with a bushing281- which' is -pressedinto the notches ofthe segment 278 by pressure exerted Vby the vspring 282. The `pressiiirc on the segment 278 is sul'licient to prevent the wipers 40. 48;"51fa'nd 274 from prematurely moving off the Contacts 283 by 'a possible: jar. pressure not, however, enough to retard theordinary operation of `the wipers. .Wheels-275 und` 276 is a double pawl 284 Whichispivoted :it 285ml 'the armature 286- 'Qne. end of the paw] 284 engages one' ratchet Wheel'fto rotate the. Wipers in one direction; Wliilefthe other engngeethe other ratchet A1"'t'oI rotate the. Wipers'in the opposite ect-ion'. The respective teeth o f thi. i' t'Clit-f'whe'els V are necessarily facing 1n 'oppoe itlirectionegas shown Vin Eigs. 5 and ei'i'ed to the center 'of the pawl 22S-lis n `gi iedprojection 287 for the 'pui-posent iidiiig between' the guide s``priii`gs` 288, 1the j fthi'tion oh whichprjectionis to tilt. the

pwihe way or the" other into engagement the other-of 'the' ratchet wheels.

t p'` t 4 te. ,infilare 289- 'od 29.0.'. @www loosely inouhteonfone endqof the'sheft 217. The manner. in which the powl284 is v.Lieooiitted with the ratchet.

tilted is-as follows: Whenthe wipers re: Il

"elng. This causes the upper end of the ui'ni" and the springs to swing inthe opposite direction to turn the puwl v'22B-L on its pivot :ind reverse the position of the piiwl :E8-Leo that it now becomes operativeto drive the Shaft in the opposite direction.-y In order to i hold the arni composed of the plates 28!) and 290'in `either ofi its positions.` there are provided zitits` lower eiid= two lockingtdogs '93 and 29% which arc adopted 'to' engagefthe are inthe shape o bell crunk `levers iiiid are pivoted between the plates 2S!) und '290 it theirlelbo'ws. Oiienrin of euch of the 'levers entends down into the path of the lugs 29;!

v and-291 on theeeginciitft; so Athat before either of these lugs strikes the arm composed ofthe plates 289 and 290 it First eiig'nxireeA the locking'dog 1nd disenguges it from-its, lli;Y 295. or 296. as the case may be. A simil! spring 297 between the dogs 293 und :31M:

serves to bring thein into' engagenientwith their respect-ive lugs when its arm is in the.

proper position. During the time when-the and 296, respectively, wl'iich'fpro-vf lect from the side ihite. These locking linge wipers are rotating, the end 'ofthe pnwl QSL which is not doing the driii'i'iig engages-lts ratchet Wheel Whenthe anim-ture 286 is in its .fully attracted position, which prevents thel Wipers from being carried forwardhv their inertia 'after t enrmatiire 286 coin" letes its-Stroke. Thus it `will be' seen that y vcontinuously energizingv and denergiz- 'ing the mngn'et'39, the Wipers of the "switch .are causedto oscillate over the hit-nk contants, The switch is also provided Withtwo relays 27 and 37, which control two groiips oftontact springs throughthe medium of their'respec'tive armatures smdfzl. Pivotally mounted on i plate u-bovet-he coilso `the relays 27 and 37 there 'is avbell crunk.

lever 306, one end of whichl engages nlug 307' on the armature 304, whilet'heother end is provided' with 1o note-h which lies iiitheL path of the 'lipt'vzirdIy-eittendingy iiriii` of lthe armature 305'of the relay 37. Tfhie endetV the lever inrmnlly forms iin'lobstriictirm for the' armature 305,so`tlx' at it'cen"inot 'he operatively nttrncted: When`the-relay His ener 'md5 its armature 304ml@ 'thelever ar enough to carry itsendoutoftlic {ith of the arrntiire 305,'A so thiitif ther@ ..2137 SIieIgiZQd at this" time itfimiy opermeiium venthieltic'ci-mico.impe are mndefwith the switch. The even contacts inyearch of the ruit groups 271,272 and 273, for example, the contacts 2,4, 6, etc'.,"serve aster'minals for trunks leading to calling devices suc'h as the dev-icev K',y while Ithe: evenfcontacts in theI group -270 are permanently grounded. The

odd'cotactsin the' groups 270,. 271 and 272, 'for example', the contacts' 1, 3,- 5,-etc., serve as terminalsfo'rtrunks leading -toffirst selec*- .tor such as the selector E, while the odd contactsin .the vgroup 273v arevpermanently grounded.

The selector switch F' (Fig. 1) isof the general ,type .of selector switch dsclosedin United States Letters Patent No.- 815,321,

granted MarchBl, 1906, to Keith, Erickson land Erickson, except' that the so-called side switch is-omitted, 'and the circuits are modl- -fiiedto adapt the switchI tooperate in a system in which the-.central office apparatus `1s controlled. by: impulses delivered over the two sides of the/line in series, .as shownin YBritish .patent-.to T. Gn Marti-n No. 10,376

of 1912,-, Amon other details the selector F comprises a ank of contacts arranged in' horizontal rows or levels, which contacts are adaptedto be engaged by a set of wipers 77, 83- and-86 carriedv upon :a shaft` (not shown) which has a vertical rr'xfovement con- -trolled bythe vertical magnet and4 a, ro-

tary movement '.-eontrolled by the rotary magnet'74.. The operations of the various partsvof theswitch-a're controlled through the medium of `the double-wound line relay 45: Means for permitting the switch to be restored to nor-mal position are provided in the release magnet 309, which, upon energizing, withdraws the retaining pawlsrom the shaft., The springs 66 and 67 close only when. the switch shaft has been raisedl onev l or more steps from its-lowest position. The

relays 56 amd64 are slow actingthat is, slow torelease-their armatures upon denergizing. The selectors F and .F-are similar toftheselectorF. v y

The connectorswitchiH (F ig. is'of the same general type-oconnector switch as4 disclosed in -United States VLetters Patent No. 815,17 6, granted lMarch .13, 1906, to Keith, Erickson-and-Erickson, the circuits, however', being modified to;l adapt the switch `to operatein a system: in which the central o'lice apparatus-isV controlled by impulses de- -livered over thetwo.sides of the line in series. Among otherdetails `the connector H comprises a bank ofl contacts arranged in horizontal.1 ows or levels, which contacts are adapted to. be engagedby a setof wipers y235, 253 and 259 .carried- 'upon ajshaft-(not sho-wn) which hasfa vertical movement con'- trolled by the, vertica-Lmagnet ,2M and .a rotary-,movement controlled .by the rotary 'magnet 21.9. .-.iflhe usual side. switch 'com prisjng the wipers.2il5,f23 8fand .252 is controlled.bythc priyate magnet,4 218 1n .the

Vusual and .well-.knownmannen The operations of the various arts of the switch are` controlled through t e medium of the double-Wound line relay 138,'said relay being connected with the line through the reversmg springs ofa socalled back-ridge relay 244, through the windings of which latter relay the called line is provided with talking current. The ringer relay 247 affords the means by which rlnging current is .applied t'o the called line. Meansfor permitting the switch to be restored to normal position are provided in vthe release"magnet 261, which, upon energizing, withdraws the retaining pawlsfrom the shaft. The springs 216close only when the switch shaft has bcen'raised one 'or 'more steps from its lowest position. The relays 154: and 213 are slow actingthat is, slow to release their armatures upon denergizing. The connector H is similar lo the connector H except that it 1s capable of twenty vertical steps.

The called substation A (Fig. 4) audits individual line switch C are similar in all respects to the calling substation A and its individual line switch 0.,'

F or the purpose of supplying battery current for operating the apparatus-and for talking purposes, there is shown the battery B havingone terminal grounded at G. For the purpose of supplying ringing current there is shown the ringing current generator L, and for the purpose of supplying busy current'thereis shown the busy machine Q. i

"A 'general Vdescription of the apparatus having been given,"it will now be explained' how connection can be'established between the line of substation A and the line'of a called substation A. The number of the called substation will be assumedl to 'be Since the automatic switching a paratus disclosed herein is in general we known in the art, and is described in the publications herein referred to, its operation will be explained in a more or less'- general manner,

When the-.subscriber at substation A 'removes the re'ce1ver2 preliminary to makin a call, an energizing circuit iscloscd throu'g i the line relay 9 of the .'-lineswitch C. This circuit extends from Aground G" through theV springs 10, conductorv 11, substation A, conductor 12, .springs 13 and the line relay 9 to battery B. The line relay 9, uponA energizing, closes a circuit from ground G' through tl'1e spr1ngs 14, pull-in winding 15 and the sprlngs 16 to battery B.. -The pull-in winding 15, upon energizing, attracts the plunger arm 18.V The lplunger arm 18, u on belng attracted, forces theplunger-whlch i's attached to the end thereof into ai' bank of trunk terminals to which it has access, forcing the springs 19, 20, -21 and 22 into engage-4 ment with the springs 23, 24, 25 and 26, respectlvely., The engagerfnent of the springs 19 and 22 with the springs 23 and spectively, closes a circuit through the lne rfelai' I' of-the secondarv` line switch E.

This circuit extends from ground Gzthrough coiul'iictor 11. substation 4the springs :28 and springs 26 and 22. conductor 12.

i springs lltand 23.- sl'irings 30aiid 31 and the with the calling line and the ,multiples o` fie rela)v 2T `to battery- B. The energization the line relay :'7 closes a circuit extendin 'froni `ground (i2 through the springs 32 an sp1-ings :'54 and 20m the point 33, thence one` branch extends over the conductor 34 to the connector private -bank contact associated the'sanie. This guartling-1iotential prevents* any party froi'n connecting with the substatioiivikwhile saidv substation is calling. An other branch extends from the point- 33 `4 throng-tithe holding winding of tlie line switch C tobattery B. This circuit through the holding winding is closed before the linerelay 9 de nergzes as a result of having its circuity opened at the springs 10 and 13. "'Iflieiela)v 9 does not deneijgiwze in'inmdiately- *upon the opening 'of its circuit. for Vthe' reason that it is slowiatirigjanjd thus 4the armature ofithe li e relax; 9 is held inlfan operated position` until. enough time-has elapsed Afor the circuitgthrough the winding to be`closech` whereby theplunger `a-rin v18 is held `iii an oper l position. A third branch (if-.the abov traced Vcircuit extends .switch does not operatenntl a ground is returned front. the` secondary.line` switch.

'.However, it will be I eadilyl seen by one v versed in the art thatfthe plunge-r ari'n 18 may beimade toco'ntrol van additional pair ofsprindtgs,A which would cause. ground to be 4placed upon vthe contact-3,6 as .soon as the plunger arii'iis @Hated-.f

AIfiirtherf res ult ofl the eneigization 'of the `line relagy.` Qifisjthe. closiiip; of a circuit from ground G2 tlirouglixthe springs 32; ref

'hay 3L springs and the rotaryfii'iagnet 3.9 f to ba'tt'eryB. Assuming that thewiper 40 is st anding upon a ljnisy contact. the relay V957 will be sliilinted by a,v circuit which vmay be ,traoedfi'oiii ground on the busy bank conta'ctztlirouglithe wiper 40. spi-ings 4 1 and 42.

uspriiigs 43andf'44. springs .17. springs 88 a nd the rotary magnet 39,1(i-lizittery B. The ro.-

tajy magnet. 39 willeneifgize over the last Vtraced `circuit and willoperate to advance lvthe. switchwi-pers one Sfp. at the same time breaking its own circuit atfth'e springs 38.,

Thusjt will y seen that the-'rotarymagn'et grounded contacts.

which the' wiper 4() has g r nently grounded, the trunks corresponding resistance of the relay rotary magnet 3 9'will not be. operatively ef- 39 will act in a manner similar to that of a buzzer to advance the switch wipers one step at a time as long the wiper 40 engages As has .previously been explained. alternate contacts in the bank t0 access are 'perinaf theretoajeading to calling devices such its the device K. The remaining contactsaaf're associated `with trunks leadin to first selet-tors such as the selector' U Iithe wiper 40 reaching the first ungroun ed con-` tact, which will he assumed leading toit'lie selector F, the shunt will vbe renioiedffrom the relay 37, which will immediately energize over the. circuit previously tiaeed The ergized when in series with it. "The irelay 37. upon" energizing, extends the line connec-tion to the line relay 45 of the first se-M v lector The circuit may be 4tlaced 'froii'l` ground Ga through the 'lower windin 4'of r`the line relay 45. springs 46 and 4;'i',` wiper the re ay 45 to battery B. The line rela-)545,

.upon-energizing. closes a circuit Vfrom ground Gf'through 'the springs 54 and-55 andthe substation A. springs` 30 and 50... wiper" 51, l Sprin s 52 and 53 and the `upperwindinlifof` relav .56? to battery BQ The energization'pt the relay 56 close.. av circuit,extendingfitink' ground G5 through the springs 57, ba'lr' dii'- tact 5S, wiper 40,l springs '4'1" and 42 and the springs 43 ando!) to fthe int 68,' where the circuit divides and one El? holding lground for the wind-ingiit overal previous traced ,circuiti The second ranch extends through the relay 37, springs 38" andthe rotaryV magnet 3910 .battervl.'

This 4circuit is closed beforethe line reiht-T27 denei-izes as a result of having its circuit opener, by the relayv 37. The linere'layQT does not (.lenergize iiiimediate'lyni'ipon the energization of the relayf' for 'the reasoi'i that it is slow acting. and thus the holding round from roimdi'G2 maintained "until g g `enoi'igh -tinie haselapsed for the completion of thecircuit rbn'i groundlG. The calling subscribernow Voperates his called number. whereby `the substation iins Y* puls-examines 6 and 7 are separatedltwile momentarily. each time breakingzthefcireui't of Vthe line relay 45' of. theselector F. The relay 56 of the selector F being slow acting interrulitions of its circuit-7b;rr the relay, and consequentlyeaoh time the. atterrelay denerg-iees an impulse is transmitted orer tht circuit extending from ground 'Gf'tlirou'i'gh the springs54 and 14-1. springs 61. springs 62 and 63,V relav 64 and the verticalv magnt- '65 to battery B. The vertical magnetrre'i ceives two impulses over this circuitgand does not denergizef during'the n'ionientir'v i? operates to raise the switch shaft and Wipers two steps to a position opposite the second row or level of bank contacts,and at the saine time the shaft-'controlled 'contacts 66 and G7 are closed. The slow acting relay 6l is maintained in its energized position continuously while impulses are being transmitted to the vertical Amagnet through it,-

and in its energized position closes a circuit extending from ground G6 through the springsI G and 69 and therela'y'70 to battory B.

forms a locking circuit for itself. extending `from ground G at the rela 56 through the springs 57, springs 71, oni-,normal springs G6, springs 72 and 73and the relay 70 to f .battery B. Thus, upon the denergization 7.1 to. battery-i3. upon energizing, rotates the shaft Wlpers -extends from ground G5 at the relay 56 through the springs 57, springs 71, off- 'normal springs (36,v4 springs 72 aind 7 3, springs 69 and 75, springs 76 andthe rotary magnet' The rotary magnet V74:,

one step, and by opening the springs 71 and .-'t'disconnectsv ground G5 ltrom itself and 30.

.from-.thefrelay .70; If the first trunk line of thesecondlerel is-idle, the -relay70 de .energizcs as soon as 4the springs 71 yare opened; `1f this trunk 4'line is' busy, however,

.the private wiperfinds the contact which .-,it-Lei-igages provided with a guarding` f-. otential which-is transmitted to t through the springs 72 and '73, thereby lproventi'ng it from deinergizing. "The rotary magnet '74., however` denergizes when'the ground ie relay springs 76 are opened, regardless of Whether the relay remains energized or not. If the -relay 70 remains energized, the circuit of the rotary magnet will be again closed as 'soon as its "armature drops back far .enough to close the sprn^gs`71 and 76. vThe rotary-magnet will, therefore, operate'ifn a manner similar -tt'rftllaifof a buzzer to advancev thev .wipe-rs' step by step y"over the cont-acts until the lnon-1grounded contact of anfidle- -trunl'` lineis `reached by the Wiper 77, *wherein onv the relay 70 denergizes. The relay. 0, upon vdenergizing, whether after oi1eor several operations of the rotary-magnet, permanently 4breaks the cirv4cuit of said rotary magnet fand closes fthe circuit" .offthef switching relay 78,. lwhich circuiti-'extends frni .'gjrol'mdv G5 Iat the reilay 56, through th'sp'rings'57, springs 71,

olf-normal 'sprin"gs-f66', springs 72 vand'79 and-the relayv78 to battery B. The relay tial-y trie switch E. vA circuit may now. be

`Wiper 8.3, springs 7 The relay 70, upon energizing,-

s'witch E. -A

5 fromith'e lingel and. extends the line' ion'tottheline' relay 80 of the 'tere nector. H through the springs 81 and 82, l 84 and 47 'to and through the substation ysprings 52 and 85,.wiper 86,- springs 87 and 88, springs 177 and the linerelay 'to battery B. The relay 80,v upon energizing, closes a circuit which may be traced from ground (Sis through the sprngs89`and 90, springs. 80 and the Wiper 7 to the point 91, Where the circuit divides and one branch extends over a' circuit previously traced to the winding 35 of the line switch and' to the relay 37 of the secondary second branch extends from the point 91 through the springs 72'and 79 and therelay 78 to battery B. :This circuit is closed before the relay 56 denergizes as a result. of having its circuit opened by the line relay 45. The relay 56 does not denergize immediately u )on the -dener ization of the line relay 45. or the reason t at it is slow acting, and thus the holding ground from ground Gr5 is maintained until enou h time has elapsed for the completion of t e vcircuit from ground G8.

A further result of the energization of the line relay 80 is the closure of a circuit from ground ,G8 through the springs 89, 90 and 92, pull-in winding 93 and thesprings 94 tobattery B. The pull-in Winding 93, upon en'erglzing attracts the plunger arm 95, which' operates to force the Springs 96, 97

and 98 into'engagement with the springs 99, 100 and '101, respectively. The engagenient7 of the springs 96 and 99 extends thel connection to the line relay 102 of the selector F. The'circuit may be traced from ground G7 through the springs 81 and 82 to 'and through the substation A, springs 87 and 88, springs- 9G and 99, springs 103and 104 and the line relay 102 to battery B. The energlzation of the line relay 102 closes= a circuit extending from ground G` through the-springs 195 and 106 and the. relay 10.7 to battery B. The energizaton of the re` lay Y 107 closes'v a circuit extending from ground G1 through.I the. springs 108 -and springs: 1.00 and 97 to the-point;` 109, where' =the circuit divides,'one branch extending.l over a previously traced `circuit to the Winding 35 of the line switch C, relay 3740i. the. line switch E and the relay 78 of the= selector F. A.- second branch of thiscircuit extends rom the point109. through the holding winding 11,0 to battery B.. This circuitisiyclosed before the li-n e relay 80 denergizes 'as a result of having its cncuit opened at the [contact springs 1 7 7. l The relay 8.0.does not. de'energize immediately upon the pulling dupof the. plunger arnrfor. the reason that it sloufactingf, and thus the holding ground ftoiuground GrE5 is "maintained until enough. time has elapsed for the completion 'of 'the circuit from ground G10'.

The calling subscriber now opcrates'his' vcalling device for the, second digit 2 of the no rates to extend the connes 'on to the rst 4,/ i e trunk in the second `le,ve ingthe saine called nui'nlie/i. The elector F thereu on to the precedingvswitches, as before extlntioialy 'while impulses are' plained.

The calling subscriber now operates his calling device for the third di it 2 ofV the called number. The selector thereupon operates to extend disconnection .to theV tirst idle trunk in the second'level in the same manner as did the` selectors F and F. Assuming that the connection is extended to the-lline relay 111 of the cally connector H, a circuit i'ny be traced from ground .G1

through the springs 81 and V812, to and through :the'substation 1 1, spi-ings 96 and 99, .springs 103 and 112, 'vri' r 113, bank contact/114, springs 115 an 116., wiper 117,

bank contact 118 and-the line relay 111 to battery B, Thedine relay 111, upon ener-A gizing, closes a circuit from Y ground (i11 through-the springs 119 and 120 and .the re- -layf-l-B'l to battery Bi The relay 121, upon energizin returns aholdingcirouit from through the sprn to .the winding 35 of the 'line switch relay 37 of the switch-E, -relay 78 of the selector F, winding110 of the line switch E', relay 123 of Vthe 'selector F `and the relay 124 of the selector The' calling subscriber. nowoperai'es his calling-device for the. fourth digit of the called number, whereby the substationimpulse springs '6 and 7 are separated twice in mentarily, 'each time breaking the circuit of the line relay 4111 of the call connector Ht The relay 1:21 being slow acting does not deenergize 'during Vthe momentiiry interi-up conse nentlyieach time the latter relay' de .ener yzes an impulse of current is trans- 131 'are nosed. 1 The. slow acting' relay 13o 'is maintained-xiii energized iton conng. trans- .init 'fthe'jvrtfical inagnet through 'it ai' from' grgnd d th 13 i ,2 1min 'e nite-mr' et s 10 Pl nge when the r1 the last impulse im beenfffaeiii Th'ejbreali'ing of' said c ilrcuitauses the private magnet 133 to denergie, thus permit- Y pass to second posiof th@ rotary magnet extends fromA groundl G through the springs 119 and 125, springs 126and 127, side switch wiper 128 (in sec ond-position), sprin 135, rotary ma net- 134 and the rela-y 1 0 to battery B. he relay 130 operates in response to the iinpulses for this digit in the same manner as' or the previous gits tocause the private magnet 133 to advance the side switch to third position.

Upon the side switch wiper 136 passing to third position, a. circuit is closed through the line relay 137 of the line switch C. circuit mag1 be tracedA from ground Grl3 at the talking connector H' through the lower Winding of the relay 13,8, springs 139 and 110,4 springs 111 and '142, springs 98 and 101, springs 143 and 114, wiper 115, bank Contact 178, springs 116 and 117, wiper 148, bank contact 149, side switch wiper 136 (in third position), wiper 1 50, bank contact 151, springs 219 and the relay 137 to battery B.

4 The'relay 138 is Iso adjusted that the current `timisef its circuit. bv the line -freisy 111, and

flow in t is circuit is not sutiicientto opera tively energize the said relay at this time. The' line `re ay 137 however energizes in se- -ries with the lower winding of the relay 138 'and closes a circuit .from ground G15 thi'ou h the springs 155, pull-in winding 156 and t e Asprings 157 .to battery B. The pull-in winding 136, upon energizing` attracts the pluner arm 159. The plunger arm 159, upon ing attracted, forces the plunger (which is attachedto the end thereo into the bunk of trunk terminals to 'which it. has-access, forcing the springs 160, 161, 165!- and 163 into eiiageznent with the springs 164, 165, 166' an 167, respectively.

` The engagement of the sprin l.throught line relay 168 of the secondary i attliesmetil'n thefshaft-eontrolled springs" 55 positionclosesra 'circuit' wu i: the-fammes '122,

line switch E. This circuit entendsfrom` 1 ground G1 through the lower winding' lof lthe v'relay 138, springs 139 and 1-10,v springs 141 and 142, springs 98 and 101, springs 143 and 1114,Wiper 145, bank Contact 178, springs 146 and 147, wiper 148,4 bankeon'tact 149, sideswitch wiper 136 (in third position)` wiper 150, bank contact 151, sprin s 160 Vand ',164, Asprings 5169 and 1570, lineA re 'ay 168 to battery B. The denei'gizing of the private' This i and 161` closes a circuit magnet 133 of the call connector H ,closes a.

Circuit from ground G1 through the-springs springsfl'Zlfnnd 172,15 ri-ngs173, private wiper 174, bankcontuct1i5und 4th'eholdii'ig iymduig 1763.150 battery 13. llw` holding winding 176, upon energizing, will hold the plungerarm 159 in an o erated position after the circuit of the p ul -in winding 156 is opened by the denergization of the line relay 137, which follows shortly. after the plunger arm 159 has broken the contact of springs 219. A second branch of the circuit from ground G extends over the previously traced circuit to the bank contact 175 and from thence throu h thesprings A161 and 165, relay 179, sprlngs 180 and the rotary magnet 181 to battery B. As this circuit is completed before that throughthe line relay 168, and therefore before a shunt isxplaced around the relay 179, it is evident that the 183, bank contact 184, springs 162 und 166 and the relay 185 to battery B. The relay 185, upon energizing, prepares a new circuit for itselfby means of the springs 186. 'i

Assumin busy contact, then, upon the energization of the line relay 168, a shunt is placedaround' the relay '179, which shunt may be traced from ground on the 'busy benk contact, Vwiper 187, springs 188 and 189,' springs 190 Aand 191,'springs 192, springs 180, rotary magnet 181 to battery B. The rotary mag# net 181 will energize over this circuit and operate to advance't'he switch wipersone str-v nt the same time breakin its own circuit at the springs 180. Thus 1t will be seen that the rotary magnet 181 will act in ay manner' similar to that of a buzzer to ad Vance the switch wipers: one step at n vtime as long as the wiper 187 en' ages grounded contacts. As' has previously alterne-te contacts in the bank to Awhich the wiper' 187 has' 'access are -p 'errnanently" grounded,- the trunks corresponding .thereto leafdi'jrg to' first seleotorssuch Aas'th'et'se-- lectrfF. The 4remaining 'contacts are' i1 s sociated with tr .vicessu'el-r 'ns-the'device' K. Upon the'wiper 187 french-ing, the f first l'ui1grounded -contct, ,which will be assumed as leading to thecalling deviceK, the shun'tiw'illH-be removed `;from.1the`reley 179,*whichgwill inirnediatelyrv .lenergize over the "circuit previous] yftri`1eed-.'

The resistance V of .the''reley 17 9 is' suctithat Iwiper 145, l'mnkrontuct 17.8, springs 146 und 'wiper 136 (i n third position) wiper that the wiper 187 of.4 the secondary line switch E2 is lstanding upon .a

terlni'ttcntly d ue tothe in een explained, through tlie` lower w1 -Up'n the. connection"beiilgiexten-ded to' the" l grilling device K a, circuit maybe traced' from ground Gf ut the faintingconnector H through the lower windingof the relay. 138, springs 139'and l40, springsv 141 und 142, springs 98 and 101, springs 143 und 1-14,

[147, wiper 148, bank contact 1-'19` side switch 150 bank contact 151, springs 16() und 164: springs 169 and 205a wiper 206, lower wind,-

ing of the relay 194, nornmlly closedsprings 203 11nd200 to batter f l,..- The lon'er winding of 1'e la. 19.4 isof conlpurutirely lo\\' resistance allowing sufficient current totlow in the above described. circuit toenergized relay 138 of the. connector H hicl 1, at- 80 trurtingl its ai.l'|i'i.ltt| |r(i,.closes the following i circuit: ground at (lf, springs 152 and 153, 4 and relay lind-ing y15-1 to battery-li., lleluy 151 in turn is energined. und prcpnres the circuits for the rertlculuntl rotary lmigncts S5 214 und which however, relu-ain open ut ythe relay 138 for the time being. A holding circuit for therclay 194 muy nl .sobetlgaljed :1t this time from gijoundli'fz through the ysprings'122 springs 171 and 172, springs 9.0 173, wiper 174builccontuct `1 75,slniiigrs 161 und 165, springs 19 3 nnd 190, springs 189 "Cnnd188, wi 1'. er 187-andthe u1 )per winding of the relay 11H-to buttery l. The relay 194,

' ay 196, sprin s 19.7 :in df198-und thespringsgV spring :200.

49711391 and 198 andl'thesp'lings 1199end200 t bfat'f 'tery/ BifThi's circu-it'is" jiniliir-tiiftlie insure that the circuit of relay 138 will .not 41,30

Lemans causes tie `circuit of the relay 188 to beA opened ut the'springs208. Upon the eleventh energization ot' the relay 190, the spring 203 enters tlic depression 209. so that the openingr ot' the springs 208 upon the followingll dcinergization will not o pen the circuit of the relay 138, for the springs 208 are now shuiited4 by the springs 200 and 203.

` From the foregoing it will be seen that the `spont'ito the impulses o'f the second circuit of the relay 138 was First closed and tlieii broken tive times momentarily, a paiise followed and -again the circuit was broken t'our times momentarily, followed by a pause The o )eration of the talking connector H due to the first group of impulses delivered by the 'calling device K will now be-explaified.v rf he,relaylliwl of the talking connectorll being slow acting does not deenergize during t-lie inoii'ientary interruptions of its circuit b v the relay 138,'and consequently each time the latter relay de-` energizes an impulse istiansinitted over the circuit'extendingfrom ground G through the springs 152 and 210, springs 211 and 212, relay 213, vert-ical magnet, 214 and the sido switch wiper 215 (in first position) to the battery B. The vertical magnet receives live impulses over this circuit `and operates tu raise the switeli shaft and ,wi ers five steps to aw'fposition opposite the ifti row or level of bank contacts,[and at the saine time the .shiift-controlled springs 2.16 -are closed. .The slow acting relay'213 is maintained iii its energiized position continuously while mii piilses"iii.'e being transmitted to the vertical magnet-through it, and in its energized position cflosesnV circuitfrom ground. (il throughl the `springs '217"a1id the private magnet 218 tobattery Bj This oircuitis brokenwhen the relay ,213,I denergzes'nfter Ythe last impulse. has beeir'rlelivefredtol the vertical niagiiet. The breaking of said circuit causes the pri vate :iiiagn'et 1218 to denergize, thus periiiittii'ig' the side; switch to pass to second position. In passing from -first tolsec'ond position` the side switch wiper 215 transfers the battery oniicctio'n,V from the vertical magneti 214 to 'the' rota ry-'niagnet 219;

VAThe apparatiisis now'in positionto roroup ofiinpulses delivered by the calling evice and, 225, springs .226, springs' 227 and circuit through the rotary magnet extends from ground G through the springs 152 and 210, springs 211 and 212, relay 213, rotary magnet 219 and the Side switch wi )er 215 (in second position) to battery B. he relay 211i operates in respoiiseto these iinpulses in the same manner as for the previous' digit to cause the, private ,magnet '218 to advance the side switch to third position. The side switch wipers 238 and 252, upon passing to third position, Complete a connection between the connector H. and the calling device K, which has already been conneetcd to the called substation A. Upon the dencrgization of the relay 213 just previous to the passing of the side switch to third position, a circuit may be traced from ground G through the springs 220, springs 231, wiper 235, upper winding of the relay 19-1 to battery B. A branch ofthe above circuit extends from the wiper 235, wiper 187, springs 188 and 189, springs 190 and 193, relay 179, springs 180 and the rotary magnet 181 to battery B. A third branch of the same circuit extends from the spring 193 through the springs 165 and lolrand the holding winding 176 to battery B. Upon the engagement of the side switch wiper 215 With its-third position Contact point, a eireiiit maybe traced from ground G through the springs 220, relay 221 and the side switch wiper 215 (in third position) to Battery B. The relay 221, upon energizing. opens the holding circuits ot' the switches E'. ii", F2 and` H, thus allowing them to return to norinal. The disen ragement ot" the springs 87 and 88 ot' the re ay 221 opens the circuit of the line relay 111 of the call -coniiector il, which, upon dciiiicigizing. opens the circuit of the relay 121. The relay 121, upon dee-iiergizinglremoves ground (im from the circuit of the winding 110, relay 123 ofy the selector-11" and the relay 121 ot' the selector F2, and in addition closes a circuit from lground G through the springs 119 and 125, springs 126 and 222, oii"iioi'iiiiil springs 131- andthe release magnet 223 to battery B.

-The release magnet 223, upon eiiergiziup:`

operates toremove the retainiiig pawls from the sbatt and its own circuit-is opened at selector F2, upon tleiicigiziiig, closes zi eircuit from ground G" through the springs 221 22S, otf-nornialsprings 229 and the release ning net 230 to battery li. The release magnet230, upon energizing operates to remove th'e re-V taining pawls troni the shaft and its own circuit is opened at the springs 2'29sieh`en the 130 l may now be traced from ground G" through the lower windin of the rela 138, springs 139 and 140, springs 141 an 82, wiper 83 to and through the substation A, w.' er 86,

'springs 87 and 231, springs 232 and 33 and the u per winding of the relay 138 to battery Ground rom G1* is now supplied through the springs 220 and thence over the ireviously'traced circuit to the winding 35 And the relay 37 and'relay 78.

'Returnin to a consideration of the calli g device it should be stated that upon the twelfth energizaton of the relay 196, the pin 2 36 causes the spring 198 to break Contact with the spring 197, thus permanently breaking the circuit of the relay 196. Furthermore, upon the twelfth energi'zation of the relay 196, thev spring 203 leaves the depression 209, thus breaking contact with the sprin 200 and removing battery from the .negative side of the trunk which was completed vby the secondary line switch EI and the primary line switch C which, until the disconnection ofthe connector H and the preceding switches, had formed part ofthe impulse circuit for the relay 138 of the' connector H. The relay 194 will remain energized throughout the conversation, and" by means of the dog 237 will prevent the wheel 201 from returning to normal;

When the side switch wiper 238v at theV talking connector H was in second position, a circuit extended `from ground G1? through the springs 220, relay 239, springs 240 and 241, side switch wiper 238 (in second posi,

tion), springs 242 and' 243 and the up r winding of the rclayv244 to battery B. he.

relay 239 operatively energizes over this cir-1 cuit, but beingof a high resistancel the relay Y 244 will not receive -sullicient current to operatively energize. The relay 239, furthermore, upon energizing, forms a locking circuit for itself, which extends from groun Gr14| through the springs 220, rela 239 and the springs 245` to battery B. vhen the yprivate m'agnet218 denergizes after the last ggoup of impulses from the calling device a circuit is completed which extends from ground Grls through the interrupter 246, ringer relay 24.7, springs 248,` springs 249 and-240 and the springsl 245 to battery B. The ringerrelay is energized intermittently due to the interrupter 246 andV oper- 'ates-to disconnect the calling 'line from the called line, and to bridge the ringing'current generator L'across the called-line to Signal the-called subscriber. Upon .the reihe switchf The relay 194, upon denergizing, allows annees u per winding of the relay 244 to battery The relay 244, upon energizin reverses the current in v the calling linean in addition opens the circuit of the ringer rela 247 and of the rely 239 at the s rings 2g pon the'coinplletion of the conversation, the. restoring of thereceiver to the switch hook at the calling substation destroys the holding circuit of the li-ne rclayz138. The line relay 138, upon denergizing, opens the circuit of the relay 154, which in tui-n, upon denergizing, removes the .holding ground from the winding 35 of the line switch C,relay 37l of the switch E, relay 78 of the selector F and the upper winding of the relay 194 of the calling device K', relay 179 of the switch E2 and the winding 176 of the line `switch'C', and in addition closes a circuit which extends from ground' G through the s rings. 15,2 and 210, spi-i 211 and 260, o -normal` springs 216 and release magnet 261 to battery B. The release magnet 261, upon denei'gizing, re-v moves the retainin and itsown-circuit is' opened at the springs tion with the selectin' F'". upon dener izing, restores line switch tonormal. The winding 35, -upon den'rgizing, releases the -plun rarin 18,1wliich, ipon returning tonorina ,places in .readiness for the next call.

The relay 37,

.they-calling device K' to return to normal. The' denergizing of the relay 179 'places the lsecoi-idar `y vswitch E* in readiness to be used again, andthe denrgizing of the holdingwinding'l allows the line switch C to return tonormal.

It having been explained how `one subscriber establishesA connection and' releases the same, it will nowA be lexplained how a connection is prevented from being made with a busy line.` If thev called number is busy, there will be a guarding potential upon the call connector private bank conice pawls from the shaft "261ywhen said shaft reaches its lowest posii.

im:l

the secondaryiis tact associated with -that line, just 4as explained ineonnection with the line switch C. -The connector pniv'atc wiper174, u' n engaging this guarded contact and be ore ,imagen uw safer fswirh has 'pissed to third vpas tion, completes an `ene'rgi'zin` through I th'e relay 262. Tliisl circuit extends `from.` ground at the private bank contact' l throughitlie wiper 174 sprin s 173' sprin 172 and263 (which are still n engageine @Ilergization of'th relayr1'30 until after the ,10 springs'. 173 make contact), lrelay 262 and the privatemagnet 133 to battery B. Thus 'it willrbe 'seen `that the private magnet 133,

locks the side switch in second o s'ition, and 'in addition the relay 262 energizes 'and connects `the busy tone with the'calling line over "fthe following', circuit: from 'groundv 2G21 Athrough the 'interrupt'en 2643`secondary ticula'rly to--thev second and third selectors,

which in mysystem are greatly -reduced in number, as they are only, operated for a very short ,tiie while the call is' beinges'-` tablished and are .then immediately released and inade accessible for' use in establishing a secondjcall. yIt will furtheiniorebe no- 4Q ticed that"thespec'ial connector which is "rinplopdforfcompleting the' shortcut to ca led-line iscnnectdt'o the' system at there. which" exchangetlie 'call is 'to' 'be'4 madethe o `eratic'in-o-f the first selector F 'esw ether' the'sll istobie made in ange 'iigwhiffch'vthisl selector is vth exchange', and tli'e`-special connector 50` when "operated, completes a directconne'ction from the .y triunk` extending from "this livret selector]to4the -calle'd line Aln'. 'this wil-y allthe otlieri,apparatusllocall connection is established'.

devised. 'niprovedrn'eans controllingcertain `of the 'automatic swltcli'esl 1n that they are controlled 4 local circuit'incluling that, is, I am enabled-1 not l only to, Aoperate non-niimericalswitch in this manner, but can `'also operate svylit'cliesv which' have two "Separate and distinct motions, one for selecthe 'calling ysubscriber `upon 4the 'banks of the tertiary line sWitchesQT tions so as toi'n'creas It will `likewise be *understood that the anni@ amena sara determined im@ ylin circuit, means ior controlling one'i'off x1- nforjextending'the connection there-j 'abledvto bexr'eleased as soon as the,

ond for selecting Aor connecting with Aatrunk in a's elected group. A"Itwill 'also be noticed that 1n 'mylsystern the secondv =and third selectors are comrnonto all the subscribers 70 of the system-ifthat is, I have a one hundred thousandsubscriber system. which consists of a plurality of exchanges, and the second- Y selectors are not only common'to all the. lines of a certainexchangef" but are also l5 accessiblefrom 'lines in any rof the other exchanges. r

Itwill be understood that if desired the 'princi le of havin 'a calling trunk connect direct y with a cal ed trunk after the called .-80

ftrur'ikV has been I-i`de1itified -indirect1`y 'and'- having the-.apparatus'which is contained in. i

`the "indirect circuit r release', is --not limited,

"to any' particular foin'of' tru'nking at any;

particular step.' Any' suitable' -trunlringf`86 operation maybe used between -f' the subscribers line's and the firstselectors R 'and the calling devices S'. `Likewise', fanys-l1i'table :form' oitrunking may be Aused between the tertiary-lineffswitchesTiand the second secondary switch in'eachg'roupi "Furtheri" more, the number of "'slubscribers in each group may be vari-ed.4 Also, if n'e'cessi1ry-,f'` may be vcut r 'separated into several Sec-'ll the trunkingcapacity.

form ofthe switches maybe' "varied, and other various changes "and modifications may b e madev without departing from the spirit ofmy invention.v 'r

What I' claim' as my' invention 1. In 'a'telephonesystem aiirst'line, a fi' circuit-,means 'for vcontro ling oneof sati'd' switches comprising `a `magnet individual A125 to'said' switch, and4 ircuitffoS-"saidpfma net including apiI nidf?thesaid'linklci "mcfluinggfsa Sad first'line. g I 3. In a' telephone system, a first line, -a

second line, a link circuit, means for 4connectin'g said lines over said link circuit, a-

circuit for controllin said means,a plurality .of switches forc osi said controlhng circuit, means for control ing said switchescomprising magnets individual thereto, and means for operating said magnets successively over a circuit includiu y 'line and a portion of said lin crcuitniiii.

series. I

4.'In a telephone'systemt'a-.rst line,al second line, elink circuit, means for con-A necting said lines over said'link circuit, a -circ'uitfor controlling said means, a plus rality ofswitches for closing said controllin circuit, means for-controlling onel of sai switches com rising a n ma et individual to said switc a circuit for said magnet'fincluding--a portion ofthe said link c rcuit, A'and means for releasing said switches s lifter said lines have been-connected and be I fling circuit, meansfor 'controlli .fore'the connection is destroyed.- v

5. In a telephone system, 'a first line, a

line, a..lin k circuit'V means .for connesting fcircuitm'for"controlling saidm means, aplurality ofxswitches `for closing said.4 controlsadflines over said link circuit, a

l' c ir'cuit`, for controlling one of i switcheisfeoingrising a magnet indiv' 3,0 .v a 4.1net' yidualtojeaid a circuit for sai .l ings;

"last circifiit including also -said inc a'iiiiffor releasing 's aid re' "the connection is de' s telephone-Systran, s first une, a

"` secendjvline, ali'nk circuit means for cons ai'd lines over said llink circuit, a circuit for controlling said means, a plu- V"ra'lity of switches for closing said contr-oli .5&1

switches comprising' magnets] individua-l y thereto, means for opeiiitin'gjsaid magnets.

successively over a vci.`1"cu"it .including said first line anda portion of "said link circuit in seri, rand v'means for releasing said "switches after said lines have been' con- 7. In a telephone trunking system,n:a vpluralityA of lines terminating in a central exchange, a lurality ofserially related trunking 'switcllies for locatin a called line, a connective circuit accessi le .to called lines' v and having a' .branch circuit, "means for extending a calling-:line into connectionwith said `connective circtt, vand' 'n'leans for o j eratintig` siiidtri'inklng switches successive y via said calling line and said branch circuit in series 8.@In\a telephonetrunking system, -a plurality f lnestemiinati'ng in a central ex* ing switches for locating a called-line, a consaid first ,b

' and the branch of'said connective circuit in seid-...linee 'have' been con` whereby the-saidcalli may be connected.

connective circuit accessi jcalling line into connection with Said coninective circuit, .means for Afurt er extending- "when a called line is coated for connectingv change, a plurality o fserially related trunkf Lavaca l plurality -ofserially vrelated `tr switches for locating va lcalled line,"a plu- 7 rality of connective circuits` accessible to called lines and each having a branch circuit, means for extending a calling line into connection with an idle connective circuit, l and means -for o erating said trunking switches successive y. over said calling: line 85 series.

10. Ina telephone trunking system, a plurality of lines terminating in a central exchange, aplurality of serially related trunking switches for locating n called line', a con J0 y nective circuit vaccessible to called-lines and having a branch circuit, 'meansv for extending a calling line into connection with saidr connective circuit, means for operatin said' E 'trunking switches siiccessively.vitil sai calles line and said branch circuitinseries,

4"and other switches oiernted automatically when' a calledf-lin'c 'is ocated for connectin the cailed'line with said connective circui Y and calle d lines 11. In a telephone trunkimg systenn-a-plurality of lines terminating 1n`acentral jex y change, a" luriility'ofserially relatedtl'ultkj I I a--calledglin le'tojcalled `lil'i'e .having a talking-conductor and having also a branch circuit directly connected to said' talking conductor, meansifor extendinga ing switc es for locatini calling linebyjway of sai branch "ein"l cuit, for operatingl said trunking s s'vit'clies,4 and 'other switches o erated 4automatica]ly the called line withvsaid connective circuit, whereby the said calling. end celled. lines may beconnected.

" 12.',In a telephone' systeu1, aV plurality of `lines terminating vin acentral 'exchan' a 12u plurality4 of. serially switches for locating rality of connective circuits accessi le .to called lines and each havingiabran circuit, meansfor extending'a calling line into' related trun inge connectionwith an' idleconnective circuit( means for operating` said vtrunlring fsi'vitchies successively .oversaid calling line and .the

branch of said connective circuit -n series.,YV

' and other switches 'operated automatically-186- r .l l 'Tii a calledfline, a plu- 65 a calling line'. into connection with sa nective circuit accessible to called lines and to having a branch circuit, means for extendhnc into connection with said-I ingr acallin connective circuit, means for operatin said trunking switches successively via sai callline and said branch circuit in series,

in oter switches operated automatically` when a called line is locatedfor connecting the called line with said connective circuit, whereby the said calling and. called lines may be connected, and means for discon- 110 nec-ting said branch. circuit to exclude said trunking switches from the connection.

14. -In a telephone trunking system, a plu rality of lines terminating in a central exchange, a plurality of serially related trunking switches for locatin a called linoE a conn'cctiife circuit accessi le to called lines liavinr a talking conductor and having a br-anci circuit directly connected to said conductor, means for extending a calling line into connection with said connective circuit, means for. further extending said calling line by way 'of said branch circuit, for operating said 4trunking switches, other switches operated automatically when a called line is located for connecting the called line with said connective circuit, whereby the said calling and called lines may be connected, and means Jfor disconnecting said branch circuitto exclude said trunk- 40 ing` switches from the connection.

15.l In' a telephone system, a plurality of lines tcri'ninating in a central exchange, a plurality ot serially related trui'iking switches tor locating a lcalled line, a pluiality ol" connective circuits accessible to callcd'lincs and each havin-g fa branch'ci'rcuitQlineanjS for er'itciidiug a calling'lin'c into connection with. an idle connective circuit, means .for operating v.said trunlcing 4switches cfsiicccssivelyover said callingg'lineg and the branch lot said rouiiectirc circuit in Series, Ottici-,switches operated automatlcally when a'called lineis located. for eoi'inecting the called line with Said connective circllit',

" Whcrcl'iy the said calling and called `lines may be connected-and means,- fordiscoi'inect .ingr said branchvcii'lcuit to yexcludesaid trunking switches'from Lthe connection.

Llti. iif a telel'ilipiie trfunli ng system,

Y "1,12 in a central excl 'ian,'n A a pluralityotm iallyli -tcdtrfunkling siifiteliesfoi' locatilig it callcdli'iic, a coin "incctive circuit accessible to cal.v `(llil'ics and having a branch circuit, ineancfone -conuection with an idle connwrtii'r 'nective circuit, means for operatin said trunking switchesI successively via sai calling liuc and said branch circuit in series, other switches operated automaticall when a called linel is located for connecting the called line with said connectiveV circuit, whereby the said calling and 'ca ll'ed lines may be connected, means for disconnecting said branch circuit toex`cl`i1de said trunking switches from the connection, and means for releasing said trunk'lng switches to ii'iake them accessibleto other calling' lines.'

17. In a telephone trunking. system, aI plurality of linee terminatingr in a central exchange, a plurality of serially related trunk ing` switches for locating' a called line, a connective circuit accessible to called'lincs having a talking'conductor and-'liavinar a branch circuit directlyy connected to said conductor,

lmeans for extending, a calling line into con1 calling and called lines may be connectei'l.

nii-,ans for disconnecting said brani-li circuit,

to exclude said trunking .\'\\'itclics'troni the connection, and means tor releasing said trunking switchesl to ma kc thcni accessible to other calling lines.

18. ln a telephone system, a plurality ot lines terminating in a central eirliange. a pluralit \l of serially related trunliii'ig switches t'or .locating a called line. a plurality of connective circuits accesailile to called linea and each having a lirancli circuit. means tor extending a calling line into circuit, iiicans for operating: said trunliing switches su(.ccssi`\'el \y over lsaid calling' line and the branch o i said connective ciicu-it,.i'|i, series, other switches operated automat llil ,when a called line is located 'for connecting;` thel allcd line with said connect-'hie cii'cuit, Minarelli'4 t'h'c said calling. and callegl lines may be connected, 'ii-leans for -d'iscon'necting4 said 'liran'chr ('.ircuit'to cxcludesai'd tiulnlling Switchesfioin theconnection, and njicansl'fo branch.

20. In a telephone trunking system, a plur'alty of linesterminating xn a central exchange, a trunk circuit for interconnecting calling and called lines, a branch of sai trunk circult, means for extending aca'lling .said connecting circuit by way of the other line into connection with said trunk circuit,

a plurality of trunkin switches accessible to said branch circuit or selectin a called line, and m'eans for operatin sai swutches over said calling line and sai branch circuit ries. to. select Ia called line, means for autoymatically operating the other series of switches to connect the saidcalled line with said. connecting circuit byway of the other branch, and means for then dlsconnecting theseriesof switches'first operated.

22'. In atei ph'onetrunking system, a plurality. of lines terminati acentral -extwobranches,v twol series automatic .line withjsnid connecting called lines, means for connecting, a, cal ling clrcult, vmeans for operating'the switches o one seriesfoversad calling `line and one of said branches in' seriejs `to selecta called line, means for. auto-v matically operating 'the' other seriesof 4.0

branch,. and means branch circuitjover operated vbefore interfearing'x with the connection over tl'l'c 'other i 235111" a' telephone trunking system, 'fa

plurality oflines terminating in agcentral l exchange, a divided connecting'circuit'having two brancheajtwo series ctautomatic..

.. switches for .extending -vsaid branchesv to.

called lines, 4 l'inewithsaid connecting circuit, means for-- `operating.; the ...switches-of one M switches upon the selection ,of a:

means for connecting -a calling series tos ect a called line, means'forf automatically-operating the' other f SWIM? frality. .0f automaticswitc called" line, forf 'e series ,seriesof' trunkline'ndtneansgfriu.he. @m4411119 it* into `1 to extend the .same into connectiinl' 'wi saidf cmnecting: circuit` by wa y .'o.f Jthe.' other" 'branch 'whereby 'the Said calling'-and called and forftlien rality of `lines terminating ina central exline with said vconnecting circuit, means for.

operati-ng the switches of one series ovei said calling line and one of said branches' in series to select a called line, means for automatically o erating thc other series of switches u on te selection of a called. line to extend t e same into connection with said connectin branch'we lines may be connected, and means for then releasing said first series of switches before destroylng said connection.

25. In a telephonetrunking system, a plurality of linesA terminating in a central cxchange, a trnk line terminating in a con? nector switch and having a branch, a plurality of automatic switches for. selecting a called line o eratingv circuits for each of said switches including the two sides of said trunk line in series, means for extending a calling line into connection with said trunk line and for further `extending it via said branch to operate said automatic` switches over said operating circuits, means includin said connector Switch 'for connecting said trunk line with the-called line, and means for then 4disconnectin' said branch. 26. In -a telephone trunk lng' .sys'l'gnxx, a plurality of lines tenninating .in-faqcentral exchange, a'trunk line terminatingin a connector switch andhavi'' alfiranclln' a P111- es ors'e'ectn a standinga calligng -vline inweonnectiomwith'said-trunk line. and switches toconnectthe said called line with) said connecting -circuit by way'. of .the other -o for disconnecting the which the .Selecting sc ries of switches were [for further. extending vasaid branch to Wtmttic switches, means in- A. Orf iflylrlsi! lines.

and called rality of'line's termatin in'acentral einl change, a trunk li 1ie termmatin` in a com.

.circut by way pf the other reby the said'callng and called 4 h"for connecting .'l'if,

current 427.4 'In-'Za' telephone trunlrin'g'susystena pluinse: anis-g 1in@ has @maaien was saidv .yf'ofswitches on withfsaid between :the

lirst switches, a third pluralityy off-switches operated to ellectincoiijunctibn with sald connectorswitch a connecti'onbetwcen the saidca'lli-n and called: lines; andmeans for i disconnecting s'aid branch. I l

29. In a tcleplionctrunking system, a plurality of lines terminating in a central exchange, a` trunk line terminating ina connector switch'and having a. branch normally connected thereto, a plurality of automatic switches for selecting a called line, a second plurality of. automatic switches for extending a calling line into connection with said trunk line and means for further extending it ria said branch to operate said first switches, a third plurality of switches operated to efi'ect iii conjunction with said connector switch a connection between the said calling and called lines, means for disconnecting said branch, and a: release control circuit common to the switches of Said second and third pluralitics. v

30. In a telephone trunking system, a plurality ofv lines terminating in .a central eX- -change, a trunk line terminating in a connector switcli and having a branch normally connected thereto, a' plurality of automatic switches for selecting a` called line, a. second pluralitiT ot' automatic switches for extending a calling line into connection with said trunk line and means for further extending it `ria sa-id branchy to operate said rst switches.1 a third plurality of switches operated to effect in conjunction with Said connector switch ay connection between the said calling and called lilies, means for disconnecting Isaid branch. a release control circuit common to the switches oit saidsecond .and third pluralitiia-s` and a relay in said connector t'or controlling said circuit..

31. lii a telephone {1i-uniting system, a plurality oie lines terminating in a central eX- change1 a` truuk line terminating in a con .liectlor Iswitch and having a branch normali)l connected thereto. a pluralityT ol automatic switches for .encircling a called line, a second pluralitr ot automatic switches for extend ing a calling line into connectionl with said trunk liuc and means for further extendingr it ria said branch to operate said first. switches.v a third l'ilurality of switches operated to c'liect in conjunction with said connector switch a connection between the said` walling id called lines, means for disconnecting ,i `lybra-rich, a release control clrcuit coninioi to the switc es of said second and .third pluralitics, and a relay in saidconnec- 1 a'fse'cond tomatica'l 'toconnect the selected called-75 i for controlling said circuit, said relay` 32. In a telephone trunking system, a plurality of subscribers lines, means including a plurality of autoinaticsivitchcs controlled by a calling line for selecting a called line,

lurality of switches operated auli'ne withl the calling line to'tlie exclusion of said first mentioned switches, and `means for releasing said second plurality of switches controlled over the said calling line.

In a telephone trunking system, a lu- 30 ra-lity of subscribers lines, means inclut ing a plurality ot' automatic switches controlled by a calling line for selecting a called line, a second plurality ofr switches operated automatically to connect the selected' called a5 line with the calling line to the exclusion of said first mentioned switches, and a pair of bridged relays in one of' said second plu-i rality of switches for supplying talking current to the lines. p

34. In a telephone system, a plurality of subscribers lines, means including a plurality automatic switches for establishing a connection between a calling and a called line, means switches for nection from including other automatic then completing a second conthe called line around certain of said first-mentioned switches,` and means releasing sald second connection confor trolled by the calling line.

35. In a telephone system, a plurality of subscribers lines, means including a plurality of automatic switches for establishing a connection between a callin line, means including ot er automatic switches for then completing a second connection from the called line around certain of said first-mentionedv switches, means for then releasing about which the second connection is established, and means for releasing said second connection controlled by the calling line.

36. In a telephone system, a plurality7 of subscribers lines, means including a plurality of switches for extending a connection to a called one of said lines, a connector switch, means for automatically operating said connector switch upon the called linwe being seized to establish a connection from the ca l ed line around certain of said firstinentioned switches, whereby a more direct connection is established between the calling and the called lilies, a source ofcurrent, and

a pair of bridged relays in said connector sviit'c'h for supplying talking current from s aid source to the Said calling and called 1 lines. l y

37.111 a telephonesystem, a pluralityofV connected calling and called 90 anda called 10.5

said Erst-mentioned switches` 110 subscribers lines; cal11i1gl l trunks'accessible 130 

